CN108616945B

CN108616945B - Method for switching communication link and related equipment

Info

Publication number: CN108616945B
Application number: CN201710075926.0A
Authority: CN
Inventors: 柳清芬
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2017-02-10
Filing date: 2017-02-10
Publication date: 2021-05-11
Anticipated expiration: 2037-02-10
Also published as: CN108616945A

Abstract

The embodiment of the invention discloses a method for switching communication links and related equipment. The method provided by the embodiment of the invention comprises the following steps: the user equipment establishes a target communication link with the core network equipment through a target base station; the user equipment establishes an incidence relation between a target communication link and a source communication link, wherein the source communication link is a communication link established between the user equipment and core network equipment through a source base station; the user equipment transmits the same data with the core network equipment through the target communication link and the source communication link; the user equipment receives the resource releasing message; and the user equipment releases the resources corresponding to the source communication link according to the resource release message. The embodiment of the invention also provides the user equipment and the core network equipment. The embodiment provided by the invention greatly reduces the interruption delay caused by the switching of the communication link.

Description

Method for switching communication link and related equipment

Technical Field

The present invention relates to the field of communications, and in particular, to a method and related device for switching a communication link.

Background

Currently, 5G technology (5-Generation New radio access technology, 5G New RAT) is referred to as New radio access technology, and can be implemented by 4th Generation mobile communication (4G) evolution.

The location of 5G technology is to provide a network that meets the traffic needs that will arise in 2020 and after 2020. The NGMN organization studied services that may appear and become mainstream after 2020 and 2020, and summarized different requirements for network characteristics with respect to their characteristics. Such as haptic internet services, electronic hygiene services, higher user mobility services, etc.

From the future 5G service types, the 5G service has a considerably higher requirement for network delay than the delay ratio that can be provided by the current 4G network, most services require that the delay provided by the network side is less than 10ms, and a small part of services that are extremely sensitive to delay require a higher requirement that the delay provided by the network side is less than 1 ms.

According to the current processing mode of 4G handover, the handover is hard handover, i.e. the connection with the source base station is disconnected first and then the target base station is connected, which causes a handover interruption delay of about 100ms in the handover process. Please refer to fig. 1a to 1d, which are schematic diagrams illustrating a 4G handover process in fig. 1a to 1 d. The process of 4G handover includes 4 processes: 1. as understood in connection with fig. 1a, the target base station 110 establishes a connection with the core network device 120; 2. as understood in fig. 1b, the User Equipment (UE) 130 releases an air interface connection with the source base station 140, and the source base station 140 forwards untransmitted data to the target base station 110; 3. as understood in fig. 1c, UE 130 accesses the target base station, and both uplink and downlink data are forwarded from target base station 110; 4. with reference to fig. 1d, it is understood that after the data forwarding on the source base station is completed, the corresponding resources are released.

As can be seen from steps 2 and 3 in fig. 1b and 1c, in the handover process, the user equipment 130 firstly disconnects the air interface connection with the source base station 140, and then establishes the air interface connection with the target base station 110, and in the process of one disconnection, the user plane data cannot be sent, and this time period is generally referred to as handover interruption delay, and is assumed to be represented by Y. And assuming that the one-way time delay consumed by the user data transmission is X when the handover is not performed, the one-way time delay consumed by the user data transmission is increased to X + Y in the handover process. In a 4G network, Y is about 100ms, and may be reduced by optimizing the interaction delay of signaling, but for a service sensitive to delay in a 5G service, the required one-way transmission delay is less than 1ms, and this delay Y is obvious and cannot meet the requirements of future network (e.g. 5G) services.

Disclosure of Invention

The embodiment of the invention provides a method for switching a communication link and related equipment. The method is used for effectively reducing the delay in the link switching process. The method for switching the communication link provided by the embodiment of the invention can be applied to networks of various systems such as 4G, 4.5G and 5G networks, future networks and the like. In the embodiment of the invention, before the communication link is switched, the user equipment already establishes the source communication link with the core network equipment through the source base station. In the switching process, the source base station establishes a target communication link with the core network equipment through the target base station on the basis that the source base station does not release the resources corresponding to the user equipment; on the user equipment side, the user equipment establishes an association relationship between a source communication link and a target communication link, and when uplink data is transmitted, the user equipment transmits the same data to core network equipment through the source communication link and the target communication link; on the core network device side, the core network device establishes an association relationship between the source communication link and the target communication link, when downlink data is transmitted, the core network device transmits the same data to the user equipment through the source communication link and the target communication link, and then the source base station releases resources corresponding to the source communication link to complete the switching process, so as to effectively reduce the delay in the communication link switching process.

In a first aspect, an embodiment of the present invention provides a method for switching a communication link, where the method includes: when the user equipment is in a connection state with the source base station, namely under the condition that the user equipment already establishes a source communication link with the core network equipment through the source base station, the user equipment establishes a target communication link with the core network equipment through the target base station; the user equipment establishes an association relation between the target communication link and the source communication link, wherein the purpose of establishing the association relation is to transmit the same data on two communication links (the target communication link and the source communication link) at the same time; that is to say, the user equipment sends to the core network device through the target communication link and the source communication link at the same time, the data sent by the two communication links are the same, or the data sent by the core network device can be received through the target communication link and the source communication link, and the data received through the two communication links are the same; the specific method for establishing the association relationship between the target communication link and the source communication link may be: because the user equipment already establishes a source communication link with the core network equipment through the source base station, that is, an Evolved Packet System (EPS) bearer is already established between the user equipment and the core network equipment, the user equipment maps the radio bearer established between the user equipment and the target base station to the EPS bearer, and the user equipment can understand that the radio bearer is associated with the identification of the EPS bearer on the target communication link, so that the user equipment can determine that the radio bearer corresponds to the same data when receiving data from the two communication links (the target communication link and the source communication link), and similarly, when sending data to the core network, the user equipment can send the same data to the core network equipment through the two communication links; then, after the user equipment receives the resource releasing message, the user equipment releases the resource corresponding to the source communication link according to the resource releasing message, and the switching process is completed. In the embodiment of the invention, in the switching process, the user equipment is accessed to the target base station while maintaining the connection with the source base station, a double link (a source communication link and a target communication link) is formed between the user equipment and the core network equipment, the user data is transmitted and received on the double link, and the source base station releases the resource corresponding to the source communication link after the switching is finished, so that the user data can be transmitted between the user equipment and the core network equipment without interruption in the switching process, and the interruption delay caused by the switching of the communication link is greatly reduced.

In a possible implementation manner, when the user equipment sends uplink data, since the user equipment sends data on the target communication link and the source communication link at the same time, when the core network equipment receives the data sent by the user equipment, the core network equipment may receive duplicate identical data, therefore, when the user equipment sends data to the core network equipment, the user equipment encapsulates the data to be transmitted, the data is data corresponding to the same EPS bearer, the data carries a sequence number identifier, the sequence number identifier starts to be numbered continuously from an initial value, and when a message is sent, the sequence number identifier is added by 1 cumulatively; and then, the user equipment sends the data carrying the serial number identification to the core network equipment through the target communication link and the source communication link, wherein the serial number identification is used for indicating the core network equipment to sequence the received data according to the serial number identification, and the repeated data is discarded according to the serial number identification, so that the core network equipment can carry out de-duplication and re-sequencing on the data, and the correctness of the core network equipment for receiving the data is improved.

In a possible implementation manner, the user equipment receives downlink data sent by the core network equipment through a dual link, receives the same data corresponding to the same EPS bearer in duplicate, and the same data all carry sequence number identifiers; the user equipment sorts the received data according to the serial number identification, and discards repeated data according to the serial number identification. To improve the correctness of the data received by the user equipment.

In a second aspect, an embodiment of the present invention provides a computer storage medium for storing computer software instructions for the ue of the first aspect, which includes a program designed to execute the first aspect.

In a third aspect, an embodiment of the present invention provides a ue, which has a function that is actually executed by the ue in the foregoing method. The function can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In a fourth aspect, a user equipment is configured to include a memory, a transceiver, and a processor. Wherein the memory is configured to store computer executable program code and is coupled to the transceiver. The program code comprises instructions which, when executed by the processor, cause the user equipment to perform the information or instructions referred to in the method of the first aspect.

In a fifth aspect, an embodiment of the present invention provides a method for switching a communication link, where the method includes: on the basis that the user equipment establishes a source communication link with the core network equipment through the source base station, the core network equipment receives a path increasing request message, the path increasing request message carries the address of a target base station and the information of the source communication link, the core network equipment determines the address of the target base station, a target communication link can be established with the user equipment through the target base station, and then the core network equipment establishes an association relationship between the target communication link and the source communication link; the specific way for the core network device to establish the association relationship between the target communication link and the source communication link may be: the source communication link information includes an EPS bearer list, because an EPS bearer is an end-to-end bearer, that is, a bearer from a user equipment end to a core network device end, it is only necessary to find the EPS bearer corresponding to the user equipment in the core network according to the EPS list, then, the core network device allocates tunnel resources between a target base station and the core network device for the EPS bearer, each EPS bearer may correspond to one tunnel resource, for convenience of description, here, taking an EPS bearer as an example, after the core network device allocates tunnel resources for the EPS bearer, a mapping relationship is established between the tunnel resources and the EPS bearer, so that the core network device may transmit data corresponding to one EPS bearer through a dual communication link at the same time. The core network equipment sends a resource releasing message to the source base station, wherein the resource releasing message is used for indicating the source base station to release resources corresponding to the user equipment so as to complete the switching of the communication link. In the embodiment of the invention, in the switching process, the user equipment is accessed to the target base station while maintaining the connection with the source base station, a double link (a source communication link and a target communication link) is formed between the user equipment and the core network equipment, the user data is transmitted and received on the double link, and the source base station releases resources corresponding to the source communication link after the switching is finished, so that the user data can be transmitted between the user equipment and the core network equipment without interruption in the switching process, and the interruption delay caused by the switching of the communication link is greatly reduced.

In a possible implementation manner, when the core network device sends downlink data, because the core network device sends data corresponding to the same EPS bearer on the target communication link and the source communication link at the same time, when the user equipment receives the data sent by the core network device, it is possible to receive the same data in duplicate, therefore, when the core network device sends data to the core network device, the core network device encapsulates the data to be transmitted, the data is the data corresponding to the same EPS bearer, the data carries a sequence number identifier, the sequence number identifier starts to be numbered continuously from an initial value, and the sequence number identifier is added by 1 cumulatively every time a message is sent; then, the core network device sends the data carrying the sequence number identification to the user device through the target communication link and the source communication link, the sequence number identification is used for indicating the user device to sequence the received data according to the sequence number identification, and the repeated data is discarded according to the sequence number identification, so that the user device can carry out de-duplication and re-sequencing on the data, and the correctness of the user device for receiving the data is improved.

In a possible implementation manner, when the core network device receives uplink data sent by the user equipment, the core network device receives the same data corresponding to the same EPS bearer in duplicate, and the same data all carry sequence number identifiers; and the core network equipment sequences the received data corresponding to the same EPS bearer according to the serial number identifier, and discards the repeated data according to the serial number identifier. To improve the correctness of the data received by the user equipment.

In a possible implementation manner, the core network device includes a first device and a second device, where the first device includes a source first device and a target first device, for example, the first device is a serving gateway, and the second device may be a PDN gateway; the target communication link is a communication link established between the user equipment and the second equipment through the target base station and the target first equipment; the source communication link is a communication link established between the user equipment and the second equipment through the source base station and the source first equipment; the second device is a core network device for establishing the association relationship between the target communication link and the source communication link. In the embodiment of the present invention, the core network device that associates the target communication link with the source communication link is not fixed but dynamically changes, and in different application scenarios, the device that associates the two communication links (the source communication link and the target communication link) is different, for example, in a handover process of a communication link based on an X2 interface, the device that associates the two communication links is a first device (e.g., a serving gateway), and in a handover process of a communication link based on an S1 interface, the device that associates the two communication links is a second device (e.g., a PDN gateway).

In a sixth aspect, an embodiment of the present invention provides a computer storage medium, which is used for storing computer software instructions for the core network device in the fifth aspect, and which includes a program for executing the fifth aspect.

In a seventh aspect, an embodiment of the present invention provides a core network device, which has a function that is actually executed by the core network device in the foregoing method. The function can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In an eighth aspect, the core network device includes a memory, an input/output interface, and a processor. Wherein the memory is configured to store computer executable program code and is coupled to the transceiver. The program code comprises instructions which, when executed by the processor, cause the core network device to perform the information or instructions referred to in the method of the fifth aspect.

Drawings

FIG. 1a is a schematic diagram illustrating a step of a handover method of a communication link in a conventional method;

FIG. 1b is a schematic diagram illustrating a step of a handover method of a communication link in a conventional method;

FIG. 1c is a schematic diagram illustrating steps of a communication link switching method in a conventional method;

FIG. 1d is a schematic diagram illustrating a step of a handover method of a communication link in a conventional method;

FIG. 2 is a block diagram of an embodiment of a communication system according to the invention;

fig. 3 is a schematic view of a scenario of a method for switching communication links according to an embodiment of the present invention;

fig. 4 is a schematic diagram of another scenario of a method for switching a communication link according to an embodiment of the present invention;

FIG. 5 is a diagram illustrating an embodiment of a user plane protocol stack model in accordance with an embodiment of the present invention;

FIG. 6 is a diagram illustrating another embodiment of a user plane protocol stack model according to an embodiment of the present invention;

fig. 7 is a schematic diagram of a format of an NCP layer packet in the embodiment of the present invention;

FIG. 8 is a flowchart illustrating steps of a method for switching communication links according to an embodiment of the present invention;

FIG. 9 is a flowchart illustrating steps of a method for switching a communication link according to another embodiment of the present invention;

fig. 10 is a schematic block diagram of another embodiment of a communication system according to the present invention;

FIG. 11 is a flowchart illustrating steps of a method for switching a communication link according to another embodiment of the present invention;

fig. 12 is a schematic structural diagram of an embodiment of a user equipment according to an embodiment of the present invention;

fig. 13 is a schematic structural diagram of another embodiment of a ue according to an embodiment of the present invention;

fig. 14 is a schematic structural diagram of another embodiment of a user equipment according to an embodiment of the present invention;

fig. 15 is a schematic structural diagram of another embodiment of a user equipment according to an embodiment of the present invention;

fig. 16 is a schematic structural diagram of an embodiment of a core network device according to an embodiment of the present invention;

fig. 17 is a schematic structural diagram of another embodiment of a core network device in an embodiment of the present invention;

fig. 18 is a schematic structural diagram of another embodiment of a core network device in an embodiment of the present invention;

fig. 19 is a schematic structural diagram of another embodiment of a core network device in the embodiment of the present invention.

Detailed Description

The embodiment of the invention provides a method for switching a communication link and related equipment, which greatly reduce interruption delay caused by switching of the communication link.

An embodiment of the present invention provides a method for switching a communication link, where the method is applied to a communication system, please refer to fig. 2, and fig. 2 is a schematic diagram of a network architecture of the communication system. It should be noted that the schematic architecture diagram in fig. 2 is only an exemplary illustration for convenience of description and is not meant to be a limiting illustration of the present invention.

The communication system comprises user equipment 210, access network equipment 220 and core network equipment 230; wherein the access network equipment comprises a source base station 2201 and a target base station 2202; the core Network device 230 includes a Mobility Management Entity (MME) 2301, a Serving Gateway (SGW) 2302, and a Packet Data Network Gateway (PGW) 2303; the MME is responsible for mobility management of a control plane, management of a user equipment context and a mobility state, and the SGW assumes a function of a core network gateway and terminates an interface in an access network direction. The PGW is a Network element connected to an external Packet Data Network (PDN), terminates an SGi interface connected to the PDN, and assumes a gateway function of the core Network. One user equipment can access multiple PDNs through multiple PGWs at the same time. The user equipment is connected with the base station through a Uu interface, the base station is connected with the service gateway through an S1-U interface, the base station is connected with the mobile management entity through an S1-MME interface, and the service gateway is connected with the PDN gateway through an S5/S8 interface. It should be noted that the interfaces and the network elements in the embodiment of the present invention are illustrated as interfaces and network elements in a 4G network, and are not limited to be described in the present application. For example, the embodiment of the invention can be applied to networks of various systems such as 4G, 4.5G, 5G networks and future networks.

In the embodiment of the invention, before switching, the user equipment is connected with the source base station, the source base station is connected with the core network equipment, and the user equipment establishes a source communication link with the core network equipment through the source base station. In the switching process, the source base station establishes a target communication link with the core network equipment through the target base station on the basis that the source base station does not release the resources corresponding to the user equipment; on the user equipment side, the user equipment establishes an association relationship between the source communication link and the target communication link, and when the uplink data is transmitted, the user equipment transmits the same data to the core network equipment through the source communication link and the target communication link; on the core network device side, the core network device establishes the association relationship between the source communication link and the target communication link, when data is transmitted, the core network device transmits the same data to the user equipment through the source communication link and the target communication link, and then the source base station releases the resource corresponding to the source communication link to complete the switching process.

For convenience of explanation, terms related to the embodiments of the present invention will be explained first. As can be understood in conjunction with fig. 3 and fig. 4, fig. 3 is a schematic view of a scenario of a method for switching a communication link, and fig. 4 is a schematic view of another scenario of the method for switching a communication link.

Source communication link: the user equipment has passed the communication link established between the source base station and the core network equipment before the handover has not taken place.

Target communication link: in the handover process, before the source base station does not release the resource corresponding to the user equipment, the user equipment passes through a communication link established between the target base station and the core network equipment.

EPS bearing: for identifying data flows using the same Quality of Service (QoS) from the user equipment to a certain external PDN link.

It should be noted that, in the application scenario shown in fig. 3, the source base station and the target base station do not perform handover across SGWs, that is, the source base station and the target base station correspond to the same SGW, the source communication link is a communication link established between the user equipment and the SGW through the source base station, and the target communication link is a communication link established between the user equipment and the SGW through the target base station. In the application scenario corresponding to fig. 3, the SGW is a device that establishes an association relationship between a source communication link and a target communication link.

In the application scenario corresponding to fig. 4, a source base station and a target base station switch across SGWs, the source base station and the target base station correspond to different SGWs, a user equipment is connected to the source base station, the source base station is connected to the source SGW, and the source SGW is connected to a PGW; then, the user equipment is connected with a target base station, and the target base station is connected with a target SGW; as can be seen from the example of the application scenario corresponding to fig. 4, the core network device that establishes an association relationship between the target communication link and the source communication link is not fixed but dynamically changed, and in different application scenarios, the devices that establish an association relationship between two communication links (the source communication link and the target communication link) are different. The application scenarios corresponding to fig. 3 and 4 are only an example, and naturally, in practical applications, there are other application scenarios, so the application scenarios corresponding to fig. 3 and 4 do not constitute a limiting description of the present application.

Further, in the user plane, in order to implement redundant transceiving of user data on each bearer dual path during handover, a pair of aggregation points needs to be correspondingly set on the network side and the user equipment side, and the aggregation points can be selected on different network elements according to different application scenarios, and the aggregation points are used for forwarding data in sequence, receiving data in sequence, discarding duplicate data, and the like, so that the data transmitted to the upper layer application is in sequence and is not duplicated. In the embodiment of the invention, a Network Convergence Protocol (NCP) layer is added to a Protocol stack between user equipment and core Network equipment, and the NCP layer is used for controlling the receiving and sending of double-link data.

Please refer to fig. 5 and fig. 6, in which fig. 5 is a schematic diagram of a user plane protocol stack model for non-SGW handover, and fig. 6 is a schematic diagram of a user plane protocol stack model for SGW handover. In order to ensure that handover interruption time delay is not introduced all the time in different application scenarios, for example, in different application scenarios of cross-SGW handover and non-cross-SGW handover, aggregation points of two paths on a network side are selected on different network elements, if handover is not cross-SGW, the aggregation point on the network side is selected on an SGW, and if handover is cross-SGW, the aggregation point on the network side is selected on a PGW.

The basic format of the NCP layer is the same no matter which network element the NCP layer is on, please refer to fig. 7 for understanding, fig. 7 is a schematic diagram of the format of the NCP layer message.

The head of the NCP layer message comprises a D/C field, an F field and an SN field, wherein the D/C field is used for indicating whether the message body data is NCP control information or NCP user data, the D indicates that the user data is transmitted, and the C indicates that the NCP control information is transmitted; the SN field is a sequence number identification field, and the F field is used to identify the length of the SN field. When the message is transmitting user data, the length of the NCP SN is variable according to the bandwidth of the transmission data. The SN serial number is numbered from 1 for data transmitted corresponding to the same bearer, and 1 is added cumulatively for each packet transmitted, for example, a first packet corresponding to one bearer is set to "1", the SN identifier is set to "2" for the 2 nd packet corresponding to the bearer, and the SN identifier is set to "2", and so on, which is not exhaustive, the SN identifier is used for transmitting data on two communication links during the period when the two communication links exist simultaneously, and the data receiving end performs deduplication and sequencing on the packets when receiving the packets. It should be noted that the format and the included fields of the NCP layer message are for illustration and are not meant to limit the present invention.

In the embodiment of the invention, in the switching process, the user equipment is accessed to the target base station while maintaining the connection with the source base station, a double link (a source communication link and a target communication link) is formed between the user equipment and the core network equipment, the user data is transmitted and received on the double link, and the source base station releases the resource corresponding to the source communication link after the switching is finished, so that the user data can be transmitted between the user equipment and the core network equipment without interruption in the switching process.

And keeping the PGW unchanged and the base station changed in the network switching process. Both MME and SGW may be changed, so that many scenarios may be deduced, and in the present embodiment, the handover procedure of the intra-SGW communication link based on the X2 interface is taken as an example for illustration.

Referring to fig. 8, an embodiment of a method for switching a communication link according to the present invention includes:

step 801, the target base station establishes a connection with the core network device.

As will be understood in conjunction with fig. 3 and 9, when there is an X2 interface between the source base station and the target base station and the handover procedure MME does not change (the target base station and the source base station are under one MME), handover between the base stations can be initiated over the X2 interface. Fig. 9 is a schematic flow chart of intra-SGW communication link handover based on the X2 interface.

In a first possible implementation, the target base station is already connected to the core network device, and only the user equipment needs to establish a connection with the target base station. In a second possible implementation manner, the user equipment establishes an air interface connection with the target base station, and the target base station establishes a connection with the core network device. In practical applications, the present application is not particularly limited to the above two connection manners, and in the embodiment of the present invention, the second implementation manner may be exemplified.

In a second possible implementation manner, the specific process of establishing connection between the target base station and the core network device may be:

1. the user equipment transmits the measurement report to the source base station.

When the ue is in a connected state with the source base station, that is, when the source communication link is established with the source base station, the ue measures the detected signal, for example, when the source signal strength is less than a first threshold and the target signal is greater than a second threshold, the ue sends a measurement report to the source base station. The ue may report the measurement report through a trigger event, or may report the measurement report periodically, and the specific manner is not limited in the embodiment of the present invention.

2. And the source base station receives the measurement report sent by the user equipment and carries out switching judgment according to the measurement report.

The source base station receives a measurement report sent by the user equipment, wherein the measurement report comprises information of the user equipment measurement, the signal strength of the current cell, the signal strength of the optional cell and the like, and then the source base station determines whether to initiate handover or not and which cell to handover to according to the measurement report.

3. The source base station sends a handover request message to the target base station, wherein the handover request message comprises information required when the target base station prepares for handover.

And the source base station determines a target base station according to the measurement report reported by the user equipment and sends a Handover Request (Handover Request) message to the target base station. The handover request message includes capability information of the ue, identification information of the ue, and the like, where the capability information indicates whether the ue supports the capability of dual-link communication. The information required by the target base station to prepare handover includes a target cell ID, a General Packet Radio System Tunneling Protocol (GTP) address and a Tunnel EndPoint Identifier (TEID) of a user plane of the SGW, and a cell required to establish a Radio bearer. After obtaining the GTP address and the TEID of the SGW, the target base station has the capability of sending an uplink message to the SGW, and creates an uplink S1-U tunnel to the SGW.

4. And the target base station receives the switching request message sent by the source base station and determines to adopt a double-link mode for switching. Specifically, in a possible implementation manner, the target base station determines whether to perform handover in a dual-link manner according to the capability information of the ue. For example, when the ue has the capability of supporting dual-link communication, the target base station determines to perform handover in a dual-link manner.

In another possible implementation manner, the target base station determines to perform handover in a dual-link manner according to the negotiation result. For example, the source base station may determine that the ue is capable of dual-link communication, and the source base station may add an identifier to a preset identifier of the handover request message, where the identifier is used to identify whether the ue is capable of dual-link communication, for example, if the identifier is "1", the ue is capable of dual-link communication, and if the identifier is "0", the ue is not capable of dual-link communication.

In another possible implementation manner, when determining that the user equipment has the capability of dual-link communication, the source base station may send a handover request message to the target base station, where the handover request message is used to instruct the target base station to perform handover in a dual-link manner. It should be noted that, in practical applications, the embodiment of the present invention is not limited to the specific method for determining the dual-path handover manner by the target base station.

5. The target base station sends a path increasing request message to the MME, wherein the path increasing request message carries the address of the target base station and the information of a source communication link, and the information of the source communication link comprises an EPS bearing list.

When the target base station decides to perform handover in a dual-link manner, the target base station sends a link addition Request message (Path Add Request) to the MME, where the message includes an EPS bearer list and a handover identifier, where the handover identifier indicates that a handover procedure of the dual-link is being performed, and the EPS bearer list includes a bearer identifier corresponding to at least one EPS bearer.

6. After receiving the link increasing Request message, the MME sends an Add access bearer Request (Add access bearer Request) message to the SGW according to the link increasing Request message, where the message carries an address of the target base station, an EPS bearer list, and a first TEID of the user plane allocated by the target base station, and the first TEID is a downlink TEID. The SGW determines the address of the target base station, and has the capability of sending downlink messages to the target base station. At this point, the target base station establishes a connection with the SGW.

Step 802, the core network device establishes an association relationship between the target communication link and the source communication link.

Please refer to fig. 9, wherein the specific steps of the SGW associating the target communication link with the source communication link include:

7. after receiving an Add access bearer Request (Add access bearer Request) message sent by the MME, the SGW finds a corresponding EPS bearer according to the EPS bearer list, and allocates second TEID information to the user plane. The second TEID is an uplink TEID.

Since the EPS bearer is an end-to-end bearer, that is, a bearer from the ue end to the PGW end, the SGW only needs to find the EPS bearer according to the EPS list, it should be noted that, in the mobile state, the reachability of data is realized through the tunnel, and the SGW establishes a GTP tunnel with the target base station (the base station to which handover is required). It can be understood that the source communication link and the EPS bearer for transmitting data in the target communication link are the same bearer, except that the intermediate network nodes are different, the network node in the source communication link is the source base station, and the network node in the target communication link is the target base station.

And the SGW finds out the corresponding EPS bearing according to the received EPS bearing list. For example, the EPS bearer list includes identifiers of 3 EPS bearers, and the SGW finds a corresponding EPS bearer according to the identifiers of the 3 EPS bearers, it should be noted that the EPS bearer list includes at least an identifier of one EPS bearer. And then the SGW allocates a second TEID for the EPS bearing, wherein the second TEID is an uplink TEID.

It can be understood that, when the SGW receives the address of the target base station and the first TEID sent by the MME, the mapping relationship is established between the EPS bearer and the first TEID, when the SGW sends downlink data to the target base station, the address of the target base station and the first TEID are filled in a destination field of the data, the address of the SGW and the second TEID are filled in a sending field of the data, the address of the SGW and the second TEID are used as destination ends of uplink data when the target base station sends uplink data, and when the target base station receives the data sent by the SGW from the tunnel resource corresponding to the first TEID, the target base station may determine that the data is data corresponding to the EPS bearer. This ensures that data on the same EPS bearer can be transmitted on both links (source communication link and target communication link) at the same time.

Further, the SGW creates an NCP layer for the EPS bearer, and establishes an association relationship between the second source link and the second target link in the NCP layer, where the NCP layer is configured to sequence data of the same bearer received by the two links and remove data with repeated sequence numbers.

It should be noted that, in this embodiment, the source communication link includes a first source link and a second source link. The first source link is a communication link between the user equipment and the source base station. The second source link is a communication link between the source base station and the core network device.

The target communication link includes a first target link and a second target link. The first target link is a communication link between the user equipment and the target base station. The second target link is a communication link between the target base station and the core network device.

8. And the SGW replies an added access bearer Response (added access bearer Response) message to the MME, wherein the message carries a second TEID (terminal identifier) distributed by the SGW for the user data.

9. And the MME replies a Path Add Request acknowledgement (Path Add Request ACK) message to the target base station, wherein the message carries the address of the SGW and second TEID information distributed by the SGW for the user data.

Step 803, the user equipment establishes a connection with the target base station.

The specific steps of establishing the connection between the user equipment and the target base station may include:

10. when the target base station receives the path increase request confirmation message replied by the MME, the target base station prepares for switching and sends a switching request confirmation (handover request acknowledgement) message to the source base station.

11. The source base station sends a Radio Resource Control (RRC) Connection Reconfiguration message (RRC Connection Reconfiguration) to the ue, where the RRC Connection Reconfiguration message is used to instruct the ue to perform handover in a dual-link manner.

12. The user equipment maintains a connection with the source base station while preparing to access resources of the target base station.

Step 804, the user equipment establishes an association relationship between the first source link and the first target link.

13. If the ue successfully accesses the target cell, the ue sends an RRC Connection Reconfiguration Complete message (RRC Connection Reconfiguration Complete) to the target base station, where the RRC Connection Reconfiguration Complete message indicates that the handover procedure is completed. And a radio bearer is established between the user equipment and the target base station.

14. The user equipment establishes an association relationship between a first source link and a first target link on an NCP layer, and the user equipment maps a radio bearer established between the user equipment and a target base station to an EPS bearer.

Step 805, the user equipment sends uplink data to the SGW over the source communication link and the target communication link.

15. After receiving the RRC connection reset complete message, the target base station sends a Path add complete message (Path add complete) to the MME, where the Path add complete message is used to indicate that the preparation of the data transmission link at the base station side is complete. The user equipment transmits uplink data through the source communication link and the target communication link. The uplink data carries a sequence number identifier, so that after the SGW receives the data, the data is sorted and deduplicated according to the sequence number identifier.

Step 806, the SGW sends the downlink data to the user equipment through the source communication link and the target communication link.

16. The MME sends a data transmission notification (Packet sent notification) message to the SGW, which indicates that the base station side data transmission link preparation is completed. After the MME sends the message to the SGW, a timer is started.

17. After the SGW receives the data transmission notification message sent by the MME, the SGW starts the user plane NCP layer to encapsulate the sequence number identifier for the packet, and sends the downlink data on the dual link, so that the downlink data carries the sequence number identifier, so that after the user equipment receives the data, the data is sorted and deduplicated according to the sequence number identifier.

Step 807, the user equipment receives the resource release message sent by the source base station.

18. And after the timer set by the MME is overtime, the MME initiates the deletion of the source communication link. The MME sends a Resource Release (Release Resource) message to the source base station.

19. And the source base station sends a Release Resource message to the user equipment and deletes the corresponding Resource.

And step 308, the user equipment releases the resource corresponding to the source communication link according to the resource release message.

20. And after receiving the Release Resource message, the user equipment disconnects the connection with the source base station and deletes the corresponding Resource. Then, the MME sends a Release Resource (Release Resource) message to the SGW. And the SGW deletes the corresponding resource after receiving the message.

21. After completing the release of the source communication link, the user equipment sends a sequence number notification message to the SGW through the NCP layer control message, and the SN sequence number of the last uplink data carrying the NCP message header is indicated in the message. The subsequent uplink user data does not carry the NCP message header.

22. SGW sends NCP sequence number notification message to user equipment, and the message indicates SN sequence number of downlink user data carrying NCP message header at last. The subsequent uplink user data does not carry the NCP message header.

Optionally, after step 21, the SGW starts a timer, and waits for receiving a sequence number notification message sent by the ue, or after the timer expires, the SGW does not activate the NCP layer to encapsulate the data, that is, does not activate the function of the NCP layer, and activates the NCP layer until the next double link handover is performed. After 22, the ue starts a timer, and waits for receiving the sequence number notification message sent by the SGW, or after the timer expires, the ue does not activate the NCP layer to encapsulate the data, i.e., does not activate the function of the NCP layer, and activates the NCP layer until the next double link handover is performed.

It should be noted that, the NCP layer described above is fixedly present, optionally, the NCP layer may also be dynamically present, where the dynamic presence refers to generating the NCP layer in a scenario where a dual link needs to be established, and when one link in the dual link is deleted, the NCP layer is correspondingly deleted.

In the embodiment of the invention, in the switching process, a source base station does not release resources corresponding to a source communication link, but on the basis that a user equipment already establishes the source communication link with an SGW through the source base station, the user equipment establishes a target communication link with the SGW through a target base station, a core network device establishes an association relationship between the target communication link and the source communication link, specifically, the SGW finds an established EPS bearer between the user equipment and the SGW, then, the core network device allocates tunnel resources for the EPS bearer, establishes a mapping relationship between the tunnel resources for transmitting user data between the target base station and the SGW and the EPS bearer, and establishes an association relationship between the target communication link and the source communication link and between the radio bearer between the user equipment and the target base station and the EPS bearer, which can be understood that the EPS bearer is an end-to-end bearer, before the handover, the user equipment and the PGW have already established an EPS bearer, and a radio bearer between the user equipment and the target base station is mapped onto the EPS bearer, and a tunnel for transmitting user data between the target base station and the SGW is mapped onto the EPS bearer, so that the user equipment and the SGW can transmit data on the same EPS bearer through a source communication link and a target communication link.

Further, the protocol stack models of the user equipment and the SGW both include an NCP layer, and when sending data, the NCP layer is used to number a packet corresponding to the same EPS bearer; when receiving data, the NCP layer is used to sort and deduplicate the packets according to the sequence number identifiers of the packets.

The embodiment corresponding to fig. 9 is an exemplary illustration of the intra-SGW handover procedure based on the X2 interface. An example illustration of a cross SGW handoff procedure based on the X2 interface is described below by way of example.

As will be understood in conjunction with fig. 4, the SGW is changed due to the handover across SGWs, that is, the source communication link is a communication link established between the user equipment and the PGW through the source base station and the source SGW. The source communication links include a first source link, a second source link, and a third source link. The first source link is a wireless link between the user equipment and the source base station, the second source link is a communication link between the source base station and the source SGW, and the third source link is a communication link between the source SGW and the PGW.

The target communication link is a communication link established between the user equipment and the PGW through the target base station and the target SGW. The target communication link comprises a first target link, a second target link and a third target link, wherein the first target link is a wireless link between the user equipment and the target base station, the second target link is a communication link between the target base station and the target SGW, and the third target link is a communication link between the target SGW and the PGW.

It should be noted that, in this embodiment, the core network devices included in the core network device at different hierarchies are only exemplified by the core network device (such as the SGW and the PGW) in the 4G network, and do not make a limiting description of the present application, and in a 5G or future network system, the name of the core network device may be different from the name of the device in the 4G network, but may be understood by combining with the exemplary description in the present application, which is exemplified by the 4G network.

The core network device may include a first device and a second device, and the first device and the second device are at different hierarchies, where the first device is a device connected to the access network device, for example, the first device is an SGW, and the second device is at a higher hierarchy than the first device, and the second device is a device directly connected to the first device. For example, the second device is a PGW. Of course, in a future network system, the core network device may further include more devices, and is not limited to the first device and the second device. If the access network device changes (from the source base station to the target base station), the convergence point of the two links is at the first device, and if the first device changes (e.g., cross-gateway switching), the convergence point of the two links is at the second device. It can be understood that, in the core network device, the aggregation point device of the two links is dynamically changed, and is not limited to a certain core network device in practical application.

In this embodiment, in an application scenario where switching is performed across gateways based on an X2 interface, a rendezvous point device of two links is a PGW.

In this embodiment, the switching process across gateways based on the X2 interface specifically includes:

step 1 to step 6 can be understood by combining step 1 to step 6 in the corresponding embodiment of fig. 9.

7. The MME sends a Create Session Request (Create Session Request) message to the target SGW, where the message carries an address of the PGW, a third TEID of the PGW side corresponding to the S5/S8 interface, and an EPS bearer list, and the third TEID is used to indicate a tunnel end point at which the target SGW sends data. That is, when the MME sends the PGW address and the third TEID to the target SGW, the target SGW has the capability of transmitting uplink data with the PGW.

8. After receiving a Create Session Request (Create Session Request) message sent by the MME, the target SGW sends an Add access bearer Request (Add access bearer Request) message to the PGW, where the message carries an address of the target SGW, a fourth TEID and an EPS bearer list, and the fourth TEID is a downlink TEID allocated by the target SGW for user data. When the PGW sends downlink data to the target SGW, the destination field of the downlink data is filled in the address and the fourth TEID of the target SGW, so that the target SGW can receive the data sent by the upstream network element (e.g., PGW).

9. After receiving an Add access bearer Request (Add access bearer Request) message sent by the target SGW, the PGW establishes an association relationship between the third source link and the third target link on the NCP layer, and allocates a fifth TEID to the target SGW, where the fifth TEID is an uplink TEID.

The NCP layer is used for analyzing the uplink user data to obtain the SN sequence number of the message header, and the PGW sorts and deduplicates the uplink user data according to the SN sequence number.

The specific method for establishing the association relationship between the third source link and the third target link in the NCP layer may be: the PGW finds a corresponding EPS bearer according to the EPS bearer list, establishes a mapping relationship between the third TEID and the EPS bearer, and when the PGW sends downlink user data, can ensure that corresponding data on the same EPS bearer can be transmitted simultaneously on the third source link and the third target link.

10. And the PGW replies an added access bearer Response (Add access bearer Response) message to the target SGW, wherein the message carries the fifth TEID.

11. And after receiving the increased access bearer Response replied by the PGW, the target SGW replies a Create Session Response (Create Session Response) message to the MME.

It should be noted that, in this embodiment, the network node devices included in the target communication link are the target base station, the target SGW and the PGW, and each node device may allocate a TEID identifier to the opposite end.

That is, in the GTP uplink, the destination field and the TEID of the user data fill in the TEID allocated by the upstream network element. In the GTP downlink path, the destination field of the user data is filled with the TEID allocated by the downstream network element.

Steps 12 to 25 can be understood in conjunction with the corresponding embodiment of fig. 9.

As will be understood with reference to fig. 10, another embodiment of the method for switching a communication link provided in the following embodiments of the present invention is an exemplary description of a procedure of switching based on an S1 interface. Please refer to fig. 10, where fig. 10 is a schematic architecture diagram of the communication system in this embodiment, and the communication system includes a user equipment 1010, an access network equipment 1020, and a core network equipment 1030. Wherein the access network equipment 1020 includes a source base station 10201 and a target base station 10202; the core network device 1030 includes a source MME 10301, a target MME 10302, a source SGW 10303, a target SGW 10304, and a PGW 10305. The embodiment may be performed when the source base station and the target base station have no X2 interface, or when the handover based on the X2 interface is unsuccessful.

Please refer to fig. 4, in this embodiment, the source communication link is a communication link between the user equipment and the source SGW and the PGW through the source target base station, and the source communication link may include a first source link, a second source link and a third source link, where the first source link is a link between the user equipment and the source base station, the second source link is a link between the source base station and the source SGW, and the third source link is a link between the source SGW and the PGW. The target communication link may include a first target link, a second target link and a third target link, where the first target link is a link between the user equipment and the target base station, the second target link is a link between the target base station and the target SGW, and the third target link is a link between the target SGW and the PGW.

Please refer to fig. 11, wherein the specific process of switching based on the S1 interface includes:

1. the user equipment sends a measurement report to the source base station.

2. The source base station sends a Handover request (Handover Required) message to a source MME according to a measurement report sent by user equipment, wherein the message carries a container transparently transmitted from the source base station to a target base station, identification information of the target base station and the like.

3. And the source MME determines a target MME according to the identification information of the target base station, the target base station is the target MME under the target MME, the target MME and the source MME can be the same MME, and the MME and the source MME can also be different MMEs. In this embodiment, a case where the source MME and the target MME are different MMEs will be described as an example. Because the message sent by the source base station is no longer sent to the target base station for executing the switching, the relocation of the core network element is involved between the MME.

If the source MME and the target MME are not the same MME, the source MME sends a switching Relocation Request (forwarded Relocation Request) message to the target MME.

That is, if the MME changes, the target base station does not report the message to the source base station, and in the subsequent process, the target base station reports the message to the target MME, and the source MME sends the information related to the user equipment to the target MME. For example, the handover relocation request carries information such as a context of the user equipment, a transparent transmission container from the source base station to the target base station, and an identifier of the target base station.

4. The target MME confirms whether the source SGW continues to serve the user equipment. If the source SGW cannot continue to serve the UE, the target MME determines a new SGW (e.g., target SGW) according to the handover relocation request.

The target MME sends a Create Session Request (Create Session Request) message to the target SGW, where the Create Session Request message (Create Session Request) message includes an address of the PGW, a sixth TEID of the PGW side corresponding to the S5/S8 interface, and context information of the user equipment.

5. After receiving a Create Session Request message (Create Session Request) message sent by the MME, the target SGW sends an Add Access Bearer Request (Add Access Bearer Request) to the PGW according to the address of the PGW and the sixth TEID.

The message carries the target SGW address and a seventh TEID allocated by the target SGW for downlink user data. The target SGW and the seventh TEID are configured to serve as a destination field of the user data when the PGW sends the downlink user data to the target SGW, so that the target SGW may receive the downlink user data sent by the PGW. To this end, a third target link between the target SGW and the PGW has been established.

6. After receiving an Add access bearer request (Add access bearer) message, the PGW establishes an association relationship between the third target link and the third source link at the NCP layer, and it can be understood that the PGW binds the third target link and the third source link at the NCP layer, where the identifier of the source communication link is "L1", the identifier of the target communication link is "L2", and the PGW associates L1 with L2. The specific method for associating the two links may be: the PGW may find the EPS bearer corresponding to the ue according to the received context information of the ue, and then map the tunnel resource allocated to the EPS bearer in the third target link to the EPS bearer, so that when the PGW sends downlink user data to the target SGW, the PGW may send data on the same EPS bearer on two communication links (the target communication link and the source communication link).

The NCP is used for encapsulating the downlink user data and encapsulating the data identification in sequence; the NCP layer is further configured to sequence and deduplicate the downlink user data when the PGW receives the uplink user data sent by the target SGW.

7. The PGW replies an Add access bearer Response (Add access bearer Response) message to the target SGW.

8. And after receiving the access bearer increasing Response message sent by the PGW, the target SGW replies a Create Session Response (Create Session Response) message to the target MME.

The created session response carries a seventh TEID allocated by the target SGW for the user plane, where the seventh TEID is an uplink TEID, and the seventh TEID is used to indicate a tunnel corresponding to the uplink user data when the target base station sends the uplink user data to the target SGW.

9. And the target MME sends a Handover Request (Handover Request) message to the target base station according to the received session creating response message, wherein the Handover Request message comprises the address of the target SGW and the seventh TEID.

10. And the target base station replies a Handover Request acknowledgement (Handover Request Acknowledge) message to the target MME according to the Handover Request, wherein the Handover Request acknowledgement message is used for indicating that the target base station is ready for Handover.

11. And the target MME sends a switching Relocation Response (forwarded Relocation Response) message to the source MME according to the switching Request confirmation message (Handover Request acknowledgement).

12. And the source MME sends a switching instruction (Handover Command) to the source base station according to the switching request confirmation message. The switching instruction is used for indicating the switching in a dual-link mode, and the switching instruction carries the address of the target base station.

13. And the source base station receives the switching instruction, does not release the resource corresponding to the user equipment, but forwards the switching instruction to the user equipment, and the switching instruction is used for indicating the user equipment to switch in a dual-link mode.

14. After receiving the Handover Command, the ue maintains the connection with the source base station, and sends a Handover Confirm (Handover Confirm) message to the target base station according to the address of the target base station, at this time, a radio bearer is established between the ue and the target base station, and the radio bearer is used for transmitting user plane data between the ue and the target base station.

15. The user equipment establishes an association relation between the first source link and the first target link at an NCP layer.

Specifically, the ue associates an identifier (e.g. L1) of the source communication link with an identifier (e.g. L2) of the target communication link, and further maps a radio bearer between the ue and the target base station to the EPS bearer, so that uplink user data sent by the ue can be transmitted over both the source communication link and the target communication link.

When user data sends uplink user data, a message corresponding to the same EPS bearer is encapsulated on an NCP layer, an SN field of the message carries a sequence number identifier, and the sequence number identifier is used for rearranging and de-duplicating the data when a PGW receives the user data.

The NCP layer is further configured to, when the user equipment receives the downlink user data, rearrange and deduplicate the received data according to the sequence number identifier of the downlink user data.

Up to this point, the user equipment may transmit uplink data through dual links (a source communication link and a target communication link).

16. After receiving a (Handover Confirm) message sent by the user equipment, the target base station sends a Handover notification (Handover Notify) message to the target MME, wherein the Handover notification message is used for indicating that the user equipment and the target base station have established an air interface connection.

17. And the target MME sends a switching Relocation completion Notification (Forward Relocation Complete Notification) to the source MME according to the switching Notification message. The relocation complete notification message is used for indicating that the user equipment connected with the source base station and the target base station have established connection.

18. After receiving the handover Relocation Complete Notification (forwarded Relocation Complete Notification) sent by the target MME, the source MME sends a handover Relocation Complete acknowledgement message (forwarded Relocation Complete acknowledgement) to the target MME.

The source MME simultaneously starts a timer that monitors the resources on the source base station and when the resources on the source SGW are released.

19. And the target MME sends a modified Bearer Request (modified Bearer Request) to the target SGW according to the forwarded Relocation Complete Notification (Forward Relocation Complete Notification), wherein the modified Bearer message carries the address of the base station of the S1-U interface of the target base station and the eighth TEID corresponding to the S1-U interface. The TEID is a downlink TEID.

20. After receiving the modified Bearer Request (modified Bearer Request) sent by the target MME, the target SGW replies a modified Bearer Response (modified Bearer Response) message to the target MME according to the modified Bearer Request (modified Bearer Request).

21. The target SGW sends a Packet sent notification (Packet sent notification) message to the PGW, where the Packet sent notification message is used to indicate that downlink data can be sent on a new link (target communication link).

Remarking: after 10 steps, the uplink data starts to be redundantly sent on two paths, and after 15 steps, the downlink data starts to be redundantly sent on the two paths.

To this end, the PGW may send downlink user data over dual links (source communication link and target communication link).

22. And when the timer set by the source MME reaches the preset time, the source MME initiates the deletion of the source communication link. The source MME sends a Resource releasing (Release Resource) message to the source base station, wherein the Resource releasing message is used for indicating the source base station to Release the Resource corresponding to the source communication link.

23. The source base station sends a Resource Release (Release Resource) message to the user equipment, wherein the Resource Release message is used for indicating the user equipment to disconnect from the source base station.

24. And the user equipment receives a Resource Release (Release Resource) message sent by the source base station, disconnects the connection with the source base station and releases the Resource corresponding to the target communication link.

Further, the source MME sends a Release Resource (Release Resource) message to the source SGW. And the source SGW deletes the resource corresponding to the source communication link after receiving the resource releasing message sent by the source MME. And simultaneously, the source SGW sends a Release Resource message to the PGW.

And after completing the resource release corresponding to the source communication link, the user equipment sends a Notify NCP SN message to the PGW through the NCP control message, wherein the message indicates the NCP SN number of the last uplink user data carrying the NCP message header. The subsequent uplink user data does not carry the NCP message header.

25. The PGW sends an NCP sequence number notification message to the user equipment, wherein the message indicates the SN sequence number of the last downlink user data carrying the NCP message header. The subsequent downlink user data does not carry the NCP message header.

26. The user equipment sends an NCP sequence number notification message to the PGW, and the message indicates the SN sequence number of the last downlink user data carrying the NCP message header. The subsequent uplink user data does not carry the NCP message header.

Optionally, after 25 steps, the PGW starts a timer, and after the timer expires, the PGW deletes the NCP layer. After step 26, the ue starts a timer, and after the timer expires, the ue deletes the NCP layer.

In this embodiment, a forwarding link, whether an indirect forwarding link or a direct forwarding link, does not need to be established between the source base station and the target base station;

before the user equipment accesses from the target, the creation of a second link (target communication link) on the network side is completed. The aggregation point of the two links is chosen on the PGW, that is to say the NCP layer is created on the PGW. After the network side resources are prepared, the user equipment continues to keep the link between the user equipment and the source base station not to be released, and simultaneously accesses the target base station to establish the connection of the air interface of the target communication link. So that the same data can be transmitted between the user equipment and the PGW through two paths during the handover process. Further, the user equipment side and the PGW side may rearrange and deduplicate the received data through the NCP layer, where the NCP layer may exist fixedly or dynamically, where dynamic existence refers to generating an NCP layer processing instance only in a scenario where dual paths need to be established, and after one of the dual paths is deleted, the NCP layer is deleted correspondingly.

In the above, a method for switching a communication link is described, and a ue to which the method is applied is described below, please refer to fig. 12, where fig. 12 is a schematic structural diagram of an embodiment of a ue 1200 according to an embodiment of the present invention. One embodiment of the user equipment comprises:

a communication module 1201, configured to establish a target communication link with a core network device through a target base station;

an association establishing module 1202, configured to establish an association relationship between the target communication link established by the communication module 1201 and a source communication link, where the source communication link is a communication link established by the user equipment and a core network device through a source base station;

a data transmission module 1203, configured to perform transmission of the same data as the core network device through the target communication link and the source communication link that are associated with each other through the association establishing module 1202;

a receiving module, configured to receive a resource release message;

and the resource releasing module is used for releasing the resources corresponding to the target communication link according to the resource releasing message received by the receiving module.

Based on the embodiment corresponding to fig. 12, please refer to fig. 13, in which another embodiment of a user equipment 1300 according to the present invention includes:

the data transmission module 1203 comprises a packaging unit 12031 and a sending unit 12032;

the encapsulating unit 12031 is configured to encapsulate data to be transmitted when the user equipment sends data to the core network device, where the data carries a sequence number identifier;

the sending unit 12032 is configured to send the data, which is encapsulated by the encapsulating unit 12031 and carries the sequence number identifier, to the core network device through the target communication link and the source communication link, where the sequence number identifier is used to instruct the core network device to sequence the received data according to the sequence number identifier, and discard the repeated data according to the sequence number identifier.

Based on the embodiment corresponding to fig. 12, please refer to fig. 14, in which another embodiment of a user equipment 1400 according to the present invention includes:

the data transmission module 1203 comprises a receiving unit 12033 and a data processing unit 12034;

a receiving unit 12033, configured to receive, through the target communication link and the source communication link, data sent by a core network device, where the data carries a sequence number identifier;

a data processing unit 12034, configured to sort the received data according to the sequence number identifier received by the receiving unit 12033, and discard duplicate data according to the sequence number identifier.

Further, the user equipment in fig. 12 to 14 is presented in the form of a functional module. A "module" as used herein may refer to an application-specific integrated circuit (ASIC), an electronic circuit, a processor and memory that execute one or more software or firmware programs, an integrated logic circuit, and/or other devices that provide the described functionality. In a simple embodiment, the user equipment of figures 12 to 14 may take the form shown in figure 15.

Embodiments of the present invention relate to a user device, which may include, but is not limited to, a mobile phone, a tablet computer, a Personal Digital Assistant (PDA), a vehicle-mounted computer, and the like.

The user equipment is a mobile phone as an example, and fig. 15 is a block diagram illustrating a partial structure of a mobile phone 1500 related to the embodiment of the present invention. Referring to fig. 15, the handset 1500 includes components such as RF (Radio Frequency) circuitry 1510, memory 1520, other input devices 1530, a display 1540, sensors 1550, audio circuitry 1560, an I/O subsystem 1570, a processor 1580, and a power supply 1590. Those skilled in the art will appreciate that the handset configuration shown in fig. 15 is not intended to be limiting and may include more or fewer components than those shown, or may combine certain components, or split certain components, or arranged in different components. Those skilled in the art will appreciate that display 1540 is part of a User Interface (UI) and that cell phone 1500 may include fewer than or the same User Interface as shown.

The following describes the respective constituent components of the mobile phone 1500 in detail with reference to fig. 15:

the RF circuit 1510 may be configured to receive and transmit signals during information transmission and reception or during a call, and in particular, receive downlink information of a base station and then process the received downlink information to the processor 1580; in addition, the data for designing uplink is transmitted to the base station. Typically, the RF circuit includes, but is not limited to, an antenna, at least one Amplifier, a transceiver, a coupler, an LNA (Low Noise Amplifier), a duplexer, and the like. In addition, RF circuit 1510 may also communicate with networks and other devices via wireless communication. The wireless communication may use any communication standard or protocol, including but not limited to GSM (Global System for Mobile communications), GPRS (General Packet Radio Service), CDMA (Code Division Multiple Access), WCDMA (Wideband Code Division Multiple Access), LTE (Long Term Evolution), email, SMS (Short Messaging Service), and the like.

The memory 1520 may be used to store software programs and modules, and the processor 1580 performs various functional applications and data processing of the mobile phone 1500 by operating the software programs and modules stored in the memory 1520. The memory 1520 may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application program required for at least one function (e.g., a sound playing function, an image playing function, etc.), and the like; the storage data area may store data (such as audio data, a phonebook, etc.) created according to the use of the cellular phone 1500, and the like. Further, the memory 1520 may include high-speed random access memory and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other volatile solid-state storage device.

Other input devices 1530 can be used for receiving entered numeric or character information and generating key signal inputs relating to user settings and function control of the handset 1500. In particular, other input devices 1530 can include, but are not limited to, one or more of a physical keyboard, function keys (such as volume control keys, switch keys, etc.), a trackball, a mouse, a joystick, a light mouse (a light mouse is a touch-sensitive surface that does not display visual output, or is an extension of a touch-sensitive surface formed by a touch screen), and the like. The other input devices 1530 are coupled to other input device controllers 1571 of the I/O subsystem 1570 and interact with the processor 1580 in signals under the control of the other device input controllers 1571.

The display screen 1540 can be used to display information entered by or provided to the user as well as various menus for the handset 100 and can also accept user input. The display screen 1540 may include a display panel 1541, and a touch panel 1542. The Display panel 1541 may be configured by LCD (Liquid Crystal Display), OLED (Organic Light-Emitting Diode), and the like. The touch panel 1542, also referred to as a touch screen, a touch-sensitive screen, etc., may collect contact or non-contact operations (e.g., operations performed by a user on the touch panel 1542 or near the touch panel 1542 by using any suitable object or accessory such as a finger or a stylus, and may also include body-sensing operations; including single-point control operations, multi-point control operations, etc.) on or near the touch panel 1542, and drive the corresponding connection device according to a preset program. Alternatively, the touch panel 1542 may include two portions of a touch detection device and a touch controller. The touch detection device detects the touch direction and gesture of a user, detects signals brought by touch operation and transmits the signals to the touch controller; the touch controller receives touch information from the touch detection device, converts the touch information into information that can be processed by the processor, sends the information to the processor 1580, and receives and executes commands sent by the processor 1580. In addition, the touch panel 1542 may be implemented by various types such as a resistive type, a capacitive type, an infrared ray, a surface acoustic wave, and the like, and the touch panel 1542 may also be implemented by any technology developed in the future. Further, touch panel 1542 may cover display panel 1541, a user may operate on or near touch panel 1542 covered on display panel 1541 according to content displayed on display panel 1541 (the display content includes, but is not limited to, a soft keyboard, a virtual mouse, virtual keys, icons, etc.), touch panel 1542 detects the operation on or near touch panel 1541 and transmits the operation to processor 1580 through I/O subsystem 1570 to determine user input, and processor 1580 then provides corresponding visual output on display panel 1541 through I/O subsystem 1570 according to the user input. Although in fig. 15, the touch panel 1542 and the display panel 1541 are implemented as two separate components to implement the input and output functions of the mobile phone 1500, in some embodiments, the touch panel 1542 and the display panel 1541 can be integrated to implement the input and output functions of the mobile phone 1500.

The cell phone 1500 can also include at least one sensor 1550, such as light sensors, motion sensors, and other sensors. Specifically, the light sensor may include an ambient light sensor that adjusts the brightness of the display panel 1541 according to the brightness of ambient light and a proximity sensor that turns off the display panel 1541 and/or the backlight when the mobile phone 1500 is moved to the ear. As one of the motion sensors, the accelerometer sensor can detect the magnitude of acceleration in each direction (generally, three axes), can detect the magnitude and direction of gravity when stationary, and can be used for applications of recognizing the posture of a mobile phone (such as horizontal and vertical screen switching, related games, magnetometer posture calibration), vibration recognition related functions (such as pedometer and tapping), and the like; as for other sensors such as a gyroscope, a barometer, a hygrometer, a thermometer, and an infrared sensor, which can be configured on the mobile phone 1500, further description is omitted here.

Audio circuitry 1560, speaker 1561, and microphone 1562 may provide an audio interface between a user and cell phone 1500. The audio circuit 1560 may transmit the converted signal of the received audio data to the speaker 1561, and convert the signal into an audio signal by the speaker 1561 and output the audio signal; on the other hand, the microphone 1562 converts collected sound signals into a signal, which is received by the audio circuit 1560 and converted into audio data, which is output to the RF circuit 1508 for transmission to, for example, another cell phone, or output to the memory 1520 for further processing.

The I/O subsystem 1570 may control input and output of external devices, including other devices, such as an input controller 1571, a sensor controller 1572, and a display controller 1573. Optionally, one or more other input control device controllers 1571 receive signals from and/or transmit signals to other input devices 1530, other input devices 1530 may include physical buttons (push buttons, rocker buttons, etc.), dials, slide switches, joysticks, click wheels, a light mouse (a light mouse is a touch-sensitive surface that does not display visual output, or is an extension of a touch-sensitive surface formed by a touch screen). It is noted that other input control device controllers 1571 may be connected to any one or more of the above devices. The display controller 1573 within the I/O subsystem 1570 receives signals from the display screen 1540 and/or transmits signals to the display screen 1540. After the display screen 1540 detects the user input, the display controller 1573 converts the detected user input into an interaction with a user interface object displayed on the display screen 1540, that is, human-computer interaction is realized. The sensor controller 1572 may receive signals from one or more sensors 1550 and/or transmit signals to one or more sensors 1550.

The processor 1580 is a control center of the mobile phone 1500, connects various parts of the entire mobile phone using various interfaces and lines, and performs various functions of the mobile phone 1500 and processes data by operating or executing software programs and/or modules stored in the memory 1520 and calling data stored in the memory 1520, thereby integrally monitoring the mobile phone. Optionally, the processor 1580 may include one or more processing units; optionally, the processor 1580 may integrate an application processor and a modem processor, where the application processor mainly processes an operating system, a user interface, an application program, and the like, and the modem processor mainly processes wireless communication. It is to be appreciated that the modem processor may not be integrated into the processor 1580.

The cell phone 1500 also includes a power supply 1590 (e.g., a battery) for powering the various components, which may be logically coupled to the processor 1580 via a power management system to manage charging, discharging, and power consumption via the power management system.

Although not shown, the mobile phone 1500 may further include a camera, a bluetooth module, etc., which are not described herein.

Further, the processor 1580 is configured to enable the ue to execute the method performed by the ue in the embodiments corresponding to fig. 8, fig. 9, and fig. 10.

Referring to fig. 16, an embodiment of the present invention further provides an embodiment of a core network device 1600, where the core network device includes:

a receiving module 1601, configured to receive a path addition request message, where the path addition request message carries an address of a target base station and information of a source communication link, and the source communication link is a communication link established with a user equipment through a source base station;

a communication module 1602, configured to establish a target communication link with the user equipment through the target base station according to the address of the target base station received by the receiving module 1601;

an association establishing module 1603, configured to establish an association relationship between the target communication link established by the communication module 1602 and the source communication link;

a data transmission module 1604, configured to perform transmission of the same data with the user equipment through the target communication link and the source communication link that are associated with each other by the association establishing module 1603;

a sending module 1605, configured to send a resource release message to the source base station, where the resource release message is used to instruct the source base station to release resources corresponding to the ue.

On the basis of the embodiment corresponding to fig. 16, please refer to fig. 17, which shows that an embodiment of the present invention further provides another embodiment of a core network device 1700, where the core network device includes:

the data transmission module 1604 comprises a packaging unit 16041 and a sending unit 16042;

the encapsulating unit 16041 is configured to encapsulate data to be transmitted when the core network device sends data to the user equipment, where the data carries a serial number identifier;

the sending unit 16042 is configured to send the data, which is encapsulated by the encapsulating unit 16041 and carries sequence number identifiers, to the user equipment through the target communication link and the source communication link, where the sequence number identifiers are used to instruct the user equipment to sequence the received data according to the sequence number identifiers, and discard the repeated data according to the sequence number identifiers.

Referring to fig. 18, on the basis of the embodiment corresponding to fig. 16, an embodiment of the present invention further provides another embodiment of a core network device 1800, where the core network device includes:

the data transmission module 1604 comprises a receiving unit 16043 and a data processing unit 16044;

the receiving unit 16043, configured to receive data sent by the user equipment through the target communication link and the source communication link, where the data carries a sequence number identifier;

the data processing unit 16044 is configured to sort the received data according to the sequence number identifier, and discard the duplicate data according to the sequence number identifier.

Further, the core network device includes a first device and a second device, where the first device includes a source first device and a target first device; the target communication link is a communication link established between the user equipment and second equipment through a target base station and target first equipment; the source communication link is a communication link established between the user equipment and second equipment through a source base station and source first equipment; the second device is a core network device for establishing an association relationship between the target communication link and the source communication link.

Further, the core network devices in fig. 16 to 18 are presented in the form of functional modules. A "module" as used herein may refer to an application-specific integrated circuit (ASIC), an electronic circuit, a processor and memory that execute one or more software or firmware programs, an integrated logic circuit, and/or other devices that provide the described functionality. In a simple embodiment, the core network apparatus of fig. 16 to 18 may take the form shown in fig. 19.

Fig. 19 is a schematic structural diagram of a core network device according to an embodiment of the present invention, where the core network device may be an SGW or a PGW. The core network device 1900 may vary widely in configuration or performance and may include one or more Central Processing Units (CPUs) 1922 (e.g., one or more processors) and memory 1932, one or more storage media 1930 (e.g., one or more mass storage devices) storing applications 1942 or data 1944. Memory 1932 and storage medium 1930 can be, among other things, transient or persistent storage. The program stored in the storage medium 1930 may include one or more modules (not shown), each of which may include a series of instructions operating on the core network devices. Further, the central processor 1922 may be configured to communicate with the storage medium 1930 to execute a series of instruction operations in the storage medium 1930 on the core network device 1900.

The core network device 1900 may also include one or more power supplies 1926, one or more input-output interfaces 1958, and/or one or more operating systems 1941, such as Windows Server, Mac OS X, Unix, Linux, FreeBSD, etc.

A central processor 1922, configured to enable the core network device to execute the method performed by the core network device in the embodiments corresponding to fig. 8, fig. 9, and fig. 10.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In the above embodiments, the data may be provided in whole or in part by software, hardware, firmware, or any of them

And calculating a combination. When implemented in software, may be implemented in whole or in part in the form of a computer program product.

The computer program product includes one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the invention to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, from one website site, computer, server, or data center to another website site, computer, server, or data center via wire (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can store or a data storage device, such as a server, a data center, etc., that is integrated with one or more available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A method of communication link handover, comprising:

the user equipment establishes a target communication link with the core network equipment through a target base station;

the user equipment establishes an incidence relation between the target communication link and a source communication link on an NCP layer, the source communication link is a communication link established between the user equipment and core network equipment through a source base station, and the NCP layer is also used for controlling data forwarding of the target communication link and the source communication link;

the user equipment transmits the same data with the core network equipment through the target communication link and the source communication link;

the user equipment receives a resource releasing message;

and the user equipment releases the resources corresponding to the source communication link according to the resource release message.

2. The method of claim 1, wherein the user equipment performs transmission of the same data with a core network device through the source communication link and the target communication link, and comprises:

when the user equipment sends data to the core network equipment, the user equipment packages the data to be transmitted, and the data carries a serial number identifier;

and the user equipment sends data carrying sequence number identification to the core network equipment through the target communication link and the source communication link, wherein the sequence number identification is used for indicating the core network equipment to sequence the received data according to the sequence number identification, and the repeated data are discarded according to the sequence number identification.

3. The method of claim 1, wherein the user equipment performs data transmission with a core network device through the source communication link and the target communication link, and wherein the method comprises:

the user equipment receives data sent by core network equipment through the target communication link and the source communication link, wherein the data carries a serial number identifier;

and the user equipment sorts the received data according to the sequence number identification, and discards repeated data according to the sequence number identification.

4. A method of communication link handover, comprising:

the method comprises the steps that core network equipment receives a path increasing request message, wherein the path increasing request message carries an address of a target base station and information of a source communication link, and the source communication link is a communication link established between user equipment and the core network equipment through the source base station;

the core network equipment establishes a target communication link with the user equipment through the target base station according to the address of the target base station;

the core network equipment establishes an incidence relation between the target communication link and the source communication link on an NCP layer, and the NCP layer is also used for controlling data forwarding of the target communication link and the source communication link;

the core network equipment transmits the same data with the user equipment through the target communication link and the source communication link;

and the core network equipment sends a resource releasing message to a source base station, wherein the resource releasing message is used for indicating the source base station to release the resource corresponding to the user equipment.

5. The method of claim 4, wherein the core network device performs the same data transmission with the user equipment through the target communication link and the source communication link, and comprises:

when the core network equipment sends data to the user equipment, the core network equipment encapsulates the data to be transmitted, and the data carries a serial number identifier;

and the core network equipment sends data carrying sequence number identification to the user equipment through the target communication link and the source communication link, wherein the sequence number identification is used for indicating the user equipment to sequence the received data according to the sequence number identification, and the repeated data are discarded according to the sequence number identification.

6. The method of claim 4, wherein the core network device performs data transmission with the user equipment through the target communication link and the source communication link, and comprises:

the core network equipment receives data sent by the user equipment through the target communication link and the source communication link, wherein the data carries a serial number identifier;

and the core network equipment sequences the received data according to the sequence number identification and discards repeated data according to the sequence number identification.

7. The method according to any of claims 4 to 6, wherein the core network device comprises a first device and a second device, and the first device comprises a source first device and a target first device;

the target communication link is a communication link established between the user equipment and second equipment through a target base station and target first equipment;

the source communication link is a communication link established between the user equipment and second equipment through a source base station and source first equipment;

the second device is a core network device for establishing an association relationship between the target communication link and the source communication link.

8. A user device, comprising:

the communication module is used for establishing a target communication link with the core network equipment through a target base station;

an association establishing module, configured to establish an association relationship between the target communication link established by the communication module and a source communication link in an NCP layer, where the source communication link is a communication link established by the user equipment and core network equipment through a source base station, and the NCP layer is further configured to control data forwarding of the target communication link and the source communication link;

the data transmission module is used for transmitting the same data with the core network equipment through the target communication link and the source communication link which are established by the association establishing module;

a receiving module, configured to receive a resource release message;

9. The UE of claim 8, wherein the data transmission module comprises an encapsulation unit and a sending unit;

the encapsulation unit is configured to encapsulate data to be transmitted when the user equipment sends data to the core network device, where the data carries a serial number identifier;

the sending unit is configured to send the data carrying the sequence number identifier, which is encapsulated by the encapsulating unit, to the core network device through the target communication link and the source communication link, where the sequence number identifier is used to instruct the core network device to sequence the received data according to the sequence number identifier, and discard the repeated data according to the sequence number identifier.

10. The UE of claim 8, wherein the data transmission module comprises a receiving unit and a data processing unit;

a receiving unit, configured to receive data sent by a core network device through the target communication link and the source communication link, where the data carries a sequence number identifier;

and the data processing unit is used for sequencing the received data according to the serial number identification received by the receiving unit and discarding repeated data according to the serial number identification.

11. A core network device, comprising:

a receiving module, configured to receive a path addition request message, where the path addition request message carries an address of a target base station and information of a source communication link, and the source communication link is a communication link established with a user equipment through a source base station;

a communication module, configured to establish a target communication link with the user equipment through the target base station according to the address of the target base station received by the receiving module;

an association establishing module, configured to establish an association relationship between the target communication link established by the communication module and the source communication link in an NCP layer, where the NCP layer is further configured to control data forwarding of the target communication link and the source communication link;

the data transmission module is used for transmitting the same data with the user equipment through the target communication link and the source communication link which are established by the association establishing module;

a sending module, configured to send a resource release message to the source base station, where the resource release message is used to instruct the source base station to release resources corresponding to the user equipment.

12. The core network device according to claim 11, wherein the data transmission module includes an encapsulation unit and a sending unit;

the encapsulation unit is configured to encapsulate data to be transmitted when the core network device sends data to the user equipment, where the data carries a serial number identifier;

the sending unit is configured to send the data carrying the sequence number identifier, which is encapsulated by the encapsulating unit, to the user equipment through the target communication link and the source communication link, where the sequence number identifier is used to instruct the user equipment to sequence the received data according to the sequence number identifier, and discard the repeated data according to the sequence number identifier.

13. The core network device of claim 11, wherein the data transmission module includes a receiving unit and a data processing unit;

the receiving unit is configured to receive data sent by the user equipment through the target communication link and the source communication link, where the data carries a sequence number identifier;

the data processing unit is configured to sort the data that can be received by the receiving module according to the sequence number identifier, and discard repeated data according to the sequence number identifier.

14. The core network device according to any of claims 11 to 13, wherein the core network device comprises a first device and a second device, the first device comprising a source first device and a target first device;

15. A user device, comprising:

a memory for storing computer executable program code;

a transceiver, and

a processor coupled with the memory and the transceiver;

wherein the program code comprises instructions that, when executed by the processor, cause the user equipment to:

establishing a target communication link with core network equipment through a target base station;

establishing an association relation between a target communication link and a source communication link in an NCP layer, wherein the source communication link is a communication link established by the user equipment and core network equipment through a source base station, and the NCP layer is also used for controlling data forwarding of the target communication link and the source communication link;

the same data transmission is carried out with the core network equipment through a target communication link and the source communication link;

receiving a resource releasing message;

and releasing the resources corresponding to the source communication link according to the resource release message.

16. A core network device, comprising:

a memory for storing computer executable program code;

a transceiver, and

a processor coupled with the memory and the transceiver;

wherein the program code includes instructions that, when executed by the processor, cause the core network device to:

receiving a path increasing request message, wherein the path increasing request message carries an address of a target base station and information of a source communication link, and the source communication link is a communication link established between user equipment and core network equipment through a source base station;

establishing a target communication link with the user equipment through the target base station according to the address of the target base station;

establishing an incidence relation between the target communication link and the source communication link at an NCP layer, wherein the NCP layer is also used for controlling data forwarding of the target communication link and the source communication link;

transmitting the same data with the user equipment through the target communication link and the source communication link;

and a resource releasing message is sent to a source base station, and the resource releasing message is used for indicating the source base station to release the resource corresponding to the user equipment.